ruby - 我如何跟踪我的堆栈跟踪高度以进行调试？

Question

我希望我的代码执行以下操作:

def debug (message)
  puts message.rjust(message.length + (stack_trace-1 * 2)) # -1 for the call to debug
end

def a
  debug "in a"
  b
  debug "end a"
end

def b
  debug "in b"
  c
  debug "end b"
end

def c
  debug "in c"
  meaningful_work
  debug "end c"
end

输出:

in a
  in b
    in c
    end c
  end b
end a

我以前用 PHP 做过，像这样:

function echon($string){
  $nest_level = count(debug_backtrace()) - 1; // minus one to ignore the call to *this* function
  echo str_repeat("  ", $nest_level) . $string . "\n";
}

据我的 google-fu 所知，没有与 debug_backtrace 等效的 Ruby。我不想修改我正在使用的代码库中的所有众多方法的调用以传递回溯 - 这是不必要的麻烦且难以恢复。

有没有我可以用来跟踪这里的全局变量？

Answer 1

只需使用 Kernel#caller使用 .length。 caller(0).length 将为您提供当前堆栈深度。

例子:

irb(main):001:0> caller(0)
=> ["(irb):1:in `irb_binding'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86:in `eval'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86:in `evaluate'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/context.rb:380:in `evaluate'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:492:in `block (2 levels) in eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:624:in `signal_status'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:489:in `block in eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:247:in `block (2 levels) in each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `loop'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:233:in `block in each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `catch'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/ruby-lex.rb:232:in `each_top_level_statement'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:488:in `eval_input'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:397:in `block in start'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:396:in `catch'", "/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb.rb:396:in `start'", "/usr/bin/irb:12:in `<main>'"]
irb(main):002:0> caller(0).length
=> 17